How to Divide Bulbs
If an established bulb planting has begun to bloom sparsely, the cause is probably overcrowding—and that means it’s time to dig and divide.
You’ll also need to divide bulbs if you want to make more plantings of a favorite kind. Because each of the five bulb types increases in a different way, techniques for division differ as well.
To divide true bulbs, carefully break apart the parent and the increase (smaller bulb) at its base. To divide lily (Lilium) bulbs, remove outer scales from the basal plate, dip the ends in rooting hormone, and plant.